1. Field of the Invention
The present invention relates to display systems comprising a transparent emissive screen which allows the display simultaneously of the information displayed by the screen and that seen by transparency therethrough.
2. Description of the Prior Art
For a long time it has been known to use in aircraft collimators allowing a sighting reticle to be formed by reflection on a semi-transparent mirror which is superimposed on the scene, a target for example, seen through the glass of the cabin. The luminosity of such a collimator may be adjusted so that the reticle is not drowned in the external light, that of the sun seen face on for example. On the other hand, the reflection from the mirrors introduces at least a partial polarization which in practice prevents the use of polarizing filters for attenuating the external light.
It has recently been proposed to use, for constructing a collimator and generally any display device called "head high", a transparent emissive screen which may be placed directly in the path of the external light rays. Thus the equipment is greatly simplified. However, the luminosity of such a screen is too low with respect to that of the sun, but there is however no phenomenon of polarization intrinsic to such a device.